Paleopedology the study of paleosols

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Paleopedology the study of paleosols
Paleosol soil that formed on a landscape of
the past
Geosol more formally defined
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Kinds of paleosols 1. Buried 2. Exhumed 3.
Relict
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Buried paleosol in alluvium
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How deep is buried?
1. According to Soil Taxonomy, 50 cm or
deeper is required
2. According to Schaetzl and Sorenson, any
depth, as long as the burying sediment is
distinct from the soil below.
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Is it Elvis? or Joe Messina?
Buried Haplorthod in a sand dune
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Buried due to post-settlement erosion upslope
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Buried here
Exhumed here
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Relict paleosols -when is a surface soil relict?
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Red soils of Georgia and Oklahoma relict
paleosols?
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Now THATS a relict paleosol!
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Relict Sangamon paleosol in western Wisconsin
(cheating a bit this one has a smidgeon of
loess of top)
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Relict paleosol in S Kentucky, or a modern soil?
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The Sangamon paleosol in Illinois the BIG one
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The Sangamon is red and thick time or climate?
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Loess
Sangamon paleosol
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Buried soil with stone line
Pedimentation (erosion) or bioturbation?
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Stacked paleosols very common
- indicates an aggrading landscape
Eustis ash pit, central NE
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Buried, partially eroded paleosols in stacked
tills, Iowa City, IA
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Oxidized colors in the paleosol above
Reduced colors in a till paleosol -wet
paleo-conditions
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Stacked paleosols in alluvium
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Paleosols in an upbuilding dune
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Buried paleosols erosion during burial why?
Notice erosion, but no stone line
Top of buried soil. (also eroded)
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Notice erosion, but no stone line
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No erosion prior to burial here! A buried
Spodosol in a dune, near Midland, MI
Small buried soil here
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Check out my blue suede shoes!
No erosion prior to burial here! A buried
Spodosol in a dune, near Midland, MI
Small buried soil here
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Other, during-burial processes, largely a
function of rate of burial. Developmental or
retardant upbuilding?
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Slow upbuilding
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Indications of upbuilding during burial
layered nature of sediments and OM above the
buried soil
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Intermittent upbuilding in a dune paleosol
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Again
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Buried paleosols problems of post-burial
alteration -additions of carbonates from
sediments above -concomitant increases in
pH -compaction -mixing with overlying sediment
(during and after burial) -loss of organic
matter via mineralization
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Buried paleosols problems of post-burial
alteration -additions of carbonates from
sediments above -concomitant increases in
pH -compaction -mixing with overlying sediment
(during and after burial) -loss of organic
matter via mineralization
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Buried paleosols problems of post-burial
alteration -additions of carbonates from
sediments above -concomitant increases in
pH -compaction -mixing with overlying sediment
(during and after burial) -loss of organic
matter via mineralization
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Buried paleosols problems of post-burial
alteration -additions of carbonates from
sediments above -concomitant increases in
pH -compaction -mixing with overlying sediment
(during and after burial) -loss of organic
matter via mineralization
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Buried paleosols problems of post-burial
alteration -additions of carbonates from
sediments above -concomitant increases in
pH -compaction -mixing with overlying sediment
(during and after burial) -loss of organic
matter via mineralization
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Sediment/soils above are impacted by
buried paleosol too! -water can perch on the
paleosol, making surface soil wetter than it
would normally be (more OM production and
weathering) -sodium in paleosol can make
overlying soil sodic -if paleosol is acidic,
acidification is enhanced in overlying soil (as
are other processes that follow-up acidification)
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Sediment/soils above are impacted by
buried paleosol too! -water can perch on the
paleosol, making surface soil wetter than it
would normally be (more OM production and
weathering) -Na in paleosol can make
overlying soil sodic -if paleosol is acidic,
acidification is enhanced in overlying soil (as
are other processes that follow-up acidification)
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Sediment/soils above are impacted by
buried paleosol too! -water can perch on the
paleosol, making surface soil wetter than it
would normally be (more OM production and
weathering) -Na in paleosol can make
overlying soil sodic -if paleosol is acidic,
acidification is enhanced in overlying soil (as
are other processes that follow-up acidification)
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Sediment/soils above are impacted by
buried paleosol too! -water can perch on the
paleosol, making surface soil wetter than it
would normally be (more OM production and
weathering) -Na in paleosol can make
overlying soil sodic -if paleosol is acidic,
acidification is enhanced in overlying soil (as
are other processes that follow-up acidification)
Indeed, in many soils in shallow loess over a
paleosol, the surface soil has developed a
fragipan where the loess is thin. (No fragipan
if loess is thick paleosol has no influence)
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Soil welding paleosol gets pedogenically
linked to the surface soil above
Buried A horizon -welded to the Bt
horizon above
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Robert V. Ruhe the godfather of soil
geomorphology
Which one is NOT Ruhe?
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Ruhes main contributions --paleosols and
geomorphic surfaces --founded field of soil
geomorphology
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Wisconsin glaciation
Kansan glaciated OLD landscapes
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Loess sources Missouri and Mississippi Rivers
Loess from older Illinoian glaciation
Loveland Loess from most recent Wisconsin
glaciation Peoria
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Overall loess thickness
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Old (gt1 Ma?) tills with eroded surfaces, S Iowa
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Whats it like in Southern Iowa?
Classic Kansan till
Classic Nebraskan till
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Sequence of events that formed the S Iowa
landscape
Classic Kansan till
Classic Nebraskan till

• Nebraskan glaciation
• Soil-forming interval in interglacial period
  (Afton paleosol)
• Kansan glaciation
• Soil-forming interval in interglacial period
  (Yarmouth paleosol)
• Illinoian glaciation (Loveland loess deposited,
  surface soil in it welds to Yarmouth paleosol
  below)
• Sangamon interglacial period (welding continues,
  resulting in the thick, red, highly polygenetic
  Yarmouth-Sangamon soil)
• Wisconsin glaciation (Peoria loess deposited)

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On stable uplands
Loveland loess here is thick enough to
separate Yarmouth and Sangamon soils -no
welded Y-S soil
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On stable uplands
Loveland loess here is thin. Thus, Sangamon soil
welds to Yarmouth soil below.
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Classic Kansan till
Classic Nebraskan till
Pedimentation event evidence?
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Prominent stone line and pedisediment
Classic Kansan till
Classic Nebraskan till
Pedimentation event evidence?
Pedimentation event when?
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Prominent stone line and pedisediment
Classic Kansan till
Classic Nebraskan till
Pedimentation event evidence?
Pedimentation event when?
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Sangamon soil forms in eroded Pre-Illinoian till
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• Nebraskan glaciation
• Soil-forming interval in interglacial period
  (Afton paleosol)
• Kansan glaciation
• Soil-forming interval in interglacial period
  (Yarmouth paleosol)
• Illinoian glaciation (UPLANDS Loveland loess
  deposited, surface soil in it welds to Yarmouth
  paleosol below)
• Illinoian glaciation (SIDESLOPES Pedimentation
  erodes soils, creates pediment and stone line)
• Sangamon interglacial period (soil formation as
  slopes stabilize Late and Middle Sangamon
  paleosol forms)
• Wisconsin glaciation (Peoria loess deposited)

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A last erosional event Holocene incision by
streams
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Y-S paleosol
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Weathering ratios Resistant
Weatherable (increases as soils get older and
more developed) (decreases with depth)
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Understanding soil geomorphology vastly improved
soil mapping
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Thank you!